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The Effects of Volatile Reaction and Stereo-Staged Combustion Technology on NO_x Emission

Author: ZhangXiaoHui
Tutor: SunShaoZeng
School: Harbin Institute of Technology
Course: Thermal Power Engineering
Keywords: NO_x Stereo staged combustion system OFA Pyrolysis Kinetic model Pulverized coal
CLC: TK224.11
Type: PhD thesis
Year: 2008
Downloads: 211
Quote: 0
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Abstract

Combined with China's current economic development and energy utilization, the development of low-cost, efficient and safe combustion removal of NO _x emissions technology has become an important target to control the discharge of pollutants. This article as a starting point, expand the mechanism of NO precipitation process of power station boiler coal-fired influencing factors, and industrial validation in different load units, developed a three-dimensional hierarchical Low the of NO _x combustion system . First TG - coupled with infrared spectroscopy (TG-FTIR) Experiment research of a high volatile bituminous expand Coasts-Redfern integral method to solve the kinetic parameters of the pyrolysis and found that when n = 1 and the correlation coefficient most good, established a heating rate of 20,40 and 80K/min pyrolysis kinetic model, the kinetic model simulation results agree well with the experimental results; same time, in-depth analysis of pyrolysis conditions on volatile product and content determined at different heating rates under the CH ₄ CO main precipitation product and nitrogen-containing compounds (NH3) accounted for a share of raw coal quality. Subsequently, the TGA test results with the results of the calculation of the FG-DVC model were compared, both in good agreement with the pyrolysis model can be used for the description of bituminous coal pyrolysis process and product. Real combustion conditions volatiles were split into groups and content calculated, using GRI3.0 reaction mechanism the PFR reactor model, calculated of different stoichiometric fuel-N conversion rate of NO formation \Found that the NO conversion rate is gradually reduced with the increase of the stoichiometric. Draw combustion method removal NO _x the high stoichiometric combustion conditions, NO _x completely transformed to stabilize takes a long time about about 0.2s , and accordingly determine a high volatile bituminous coal, in order to achieve lower NO _x emissions purposes, from the primary combustion zone to a burnout zone, the residence time can not be less than 0.32s conclusions. Thus establishing a staged combustion system solutions for utility boilers stereo. Industrial Experimental Study carried out in the storage bunker and Pulverizing System boiler unit, to ensure stable operation of units on the basis of NO _x emission concentration achieved a significant reduction, of which 50MW in storage bunker milling system boiler unit NO _x emissions control in the 450mg/m3 following; transform 200MW Pulverizing System boiler unit, can be to of NO _x emissions control below 350mg/m3 effective, can be reduced to a minimum so 250mg/m3, achieved great economic and social benefits, to verify the reliability of the research program of the early mechanism in a different capacity units. Finally, using the verified model and calculation methods of different capacity units on combustion and NO _x emissions simulation using FLUENT combination of FG-DVC pyrolysis model processing platform on NO _x emissions level simulation, and results in good agreement with the experimental values ??to verify the stability and reliability of the model. Laid the basis of the simulation study for low NO _x combustion technological transformation results forecast. This study provide a theoretical basis and technical reference work on the extension and application of the dimensional classification low the of NO _x combustion technology, reducing utility boilers NO _x emissions and improve combustion efficiency and reduce energy consumption .

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CLC: > Industrial Technology > Energy and Power Engineering > Steam Power Engineering > Steam boiler > Furnace process and pot process > Furnace process > Combustion process
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